Lumbar Puncture
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More Specific Terms
Indications
-
- inflammatory conditions:
- miscellaneous conditions:
- pseudo tumor cerebri, normal pressure hydrocephalus
- introduction of diagnostic & therapeutic agents
Contraindications
- Evidence of increased intracranial pressure
- papilledema
- focal neurologic signs
- CT suggests increased intracranial pressure*
- infected skin or tissue overlying puncture site
- anticoagulated state
- increased prothrombin time
- reverse anticoagulation 1 hr prior to LP
- thrombocytopenia
Procedure
- A 20-22 gauge needle with stylet inserted is inserted using sterile technique into the lumbar cistern of the spinal cord for diagnostic or therapeutic purposes. The spinal cord ends at L1-L2 in adults, L3 in children. The needle is inserted into the L4-L5 or the L3-L4 interspace. The L2-L3 space may be used in adults. The superior aspects of the iliac crests marks the level of the L4-L5 interspace. Local anesthesia with lidocaine is standard procedure & narcotic analgesia is usually greatly appreciated. Opening pressure of the CSF may be measured with a manometer. Normal pressures are 10-20 cm of H2O. 1-2 mL of CSF is collected in tubes 1-3 & 4 mL of fluid is collected in tube for special studies.
Complications
- headache occurs 10-20% of the time
- hydration, supine position & small gauge needle are most useful measures
- infection
- bleeding
- backache
- epidermal transplant: stylet is used to prevent epidermal transplant into the spinal canal
- paresthesias: use stylet, do not aspirate CSF or nerve roots
- herniation:*
- avoid LP if mass lesion or acutely elevated intracranial pressure is suspected
- CT of head prior to LP to identify mass lesions
- * 1) head CT prior to LP is indicated, except:
- if clinically suspected meningitis, & low risk of abnormal CT [2]
- performance of a head CT prior to LP delays administration of antibiotics by about 1 hour
More General Terms
Additional Terms
References
- Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1065-67
- Journal Watch 22(2):17, 2002 Hasbun et al, N Engl J Med 345:1727, 2001
- National Guideline Clearinghouse (1) Assessment: prevention of post-lumbar puncture headaches. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. (2) Addendum to assessment: prevention of post-lumbar puncture headaches. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. ngc-guideline: [1]
